We also derive a strong Schottky result for \(\mathbb {R}\) -buildings. Isometries of \(\mathbb {R}\) -buildings map apartments to apartments [1]}, and if the building at infinity is thick, they also map Weyl chambers to Weyl chambers [2]}. As in [3]}, we call an isometry \(f\)  generic if none of its parallel axes are contained in any wall of any apartment of \(X\) . An isometry \(f\)  is generic if and only if \(f\)  has a unique invariant apartment \(\mathcal {A}_f\)  [2]}. A generic isometry \(f\)  determines,
for any fixed choice of basepoint \(x\in \mathcal {A}_f\) , a pair of chambers in \(\mathrm {link}(x)\) . We say
that generic isometries \(f\)  and \(g\)  are opposite if \(\mathcal {A}_f \cap \mathcal {A}_g = \lbrace x\rbrace \)  and each of the
chambers determined by \(f\)  is opposite in \(\mathrm {link}(x)\)  to each of the chambers determined
by \(g\) .
